Diffraction grating

About: Diffraction grating is a research topic. Over the lifetime, 24884 publications have been published within this topic receiving 372437 citations. The topic is also known as: grating.

Broad-range wavelength-tunable superstructure grating (SSG) DBR lasers

Abstract: A broad tuning range is demonstrated in tunable DBR lasers with a novel superstructure grating (SSG). These SSG reflectors were fabricated by electron-beam lithography, and grating performance was evaluated by measuring the transmittance characteristics of a ridge-type SSG reflector. Incorporating this SSG reflector into distributed-Bragg-reflector (DBR) laser results in lasers that can be tuned over a wide wavelength range by using coarse and fine tuning mechanisms. Wavelength-tunable SSG DBR lasers were fabricated and operated under low-threshold CW conditions. Wavelength tuning ranges of 50 and 100 nm were designed and experimentally measured to be 50 and 83 nm, respectively, with single-mode operation. >

Volume-phase holographic gratings and their potential for astronomical applications

Abstract: A diffraction grating technology based upon volume-phase holograms shows promise of enhanced performance for many applications in astronomical spectroscopy over classical surface-relief grating technology. We present a discussion of the underlying physics of a volume-phase grating, give some theoretical performance characteristics, present performance data for a real volume-phase grating, and discuss some potential applications for this grating technology.

Polarization-insensitive arrayed-waveguide grating wavelength multiplexer on silicon

Abstract: A wavelength-division multiplexer with no polarization dependence is demonstrated. It is based on an arrayed-waveguide grating fabricated with silica-based optical waveguides on a silicon substrate. The polarization dependence that is due to the birefringence of the waveguide is eliminated by inserting a quartz λ/2 plate in the middle of the arrayed waveguide. Moreover the grating is designed to operate in the 115th order for high wavelength resolution. The polarization insensitivity and the high resolution lead to the successful multiplexing of 13 wavelength channels with 1-nm spacing. A passband width of 0.3 nm and a cross-talk level of −30 dB are achieved.

Blazed gratings and Fresnel lenses fabricated by electron-beam lithography

Abstract: A blazing technique using electron-beam lithography to achieve higher efficiency of gratings and Fresnel lenses is described. Transmission-type blazed gratings have been formed in polymethyl methacrylate films. As a result of measurement, we found that their diffraction efficiency of the first order in these gratings amounts to as much as 60 to 70% at 0.633 microm. Fresnel lenses of 1-mm diameter and 5-mm focal length, which have a sawtooth relief profile, have been also fabricated, and the experimental results showed high-efficiency performance (about 50%) and nearly diffraction-limited focusing.

Liquid-crystal blazed-grating beam deflector

Abstract: A transmission-type nonmechanical multiple-angle beam-steering device that uses liquid-crystal blazed grating has been developed. Sixteen steering angles with a contrast ratio of 18 has been demonstrated. A detailed analysis of the liquid-crystal and poly(methyl methacrylate) blazed-grating deflector was carried out to provide guidance during the deflector’s development. A manufacturing offset compensation technique is proposed to improve the device’s performance greatly. A hybrid approach utilizing electrically generated blazed grating combined with the cascading approach described here yields in excess of 500 deflecting angles.